# Saturday Science: Air Pressure

The air pressure surrounding us is typically 14.7 pounds per square inch; however, this can be altered by a number of different factors. For instance, when the wind blows or when a car accelerates.

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Higher air pressure is caused by a push or force against an object. Likewise, when the air particles are sped up, it creates less “push”.

One easy way to understand this is by imagining that fast-moving air particles are in such a hurry that they are not able to apply force – this was the same principle that created airplanes.

When a plane travels along the runway, the air on top of the wings is sped up, lowering the pressure and allowing the air under the wing to push air upwards.

What’s more interesting than hearing these principles is testing them out for yourself.

With this in mind, for this Saturday’s science, (see also: Saturday Science: Sea Monkeys)we will be learning about air pressure with the help of some fun activities.

Let’s get started.

## 1. Indoor Tornado Experiment

This experiment allows you to make a tornado in a bottle.

### Materials

• Transparent jar
• Water
• Food coloring
• Liquid dish soap
• Vinegar

### Directions

1. Fill your jar two-thirds full with water. Then, add several drops of whatever food coloring you desire.
2. Then, add one tablespoon of liquid dish soap to the water and a teaspoon of vinegar.
3. Secure the lid on the jar. Make sure it is tightly on to prevent any possible leaks and messes.
4. Then all you have to do is give the jar a shake and then twist it – this should cause the liquid inside to start spinning and create a small vortex.

## 2. Water Glass Trick

In some instances, the pressure of air is stronger than gravity. With this experiment, you’ll be able to ‘magically’ hold an index card in place by itself even when tipped upside down.

• A cup
• Water
• Index card

### Directions

1. Fill a cup with two-thirds of water.
2. Cover the top of the cup using an index card.
3. Hold the card in place and then take it to a sink to tip it upside down.
4. Remove your hand from underneath the cup.

Since the water is lighter than the air outside the cup, the card remains in place. This is because there is 15 pounds of force of air pushing against the card, while the force of the water is only about one pound pushing down.

## 3. Magic Egg Experiment

For this experiment, you’ll be using the force of air pressure to help push an egg through the neck of a bottle.

Below, you’ll find all the materials you’ll need when it comes to performing this experiment.

### Materials

• A bottle
• A hard-boiled egg
• A match

### Directions

1. Remove the shell of your hard-boiled egg.
2. Light a match and throw it into the bottom of a bottle.
3. Place your peeled egg onto the opening of the bottle – making sure the small end of the egg is facing down.
4. After a few seconds, the egg should pop straight into the bottle.

Once the air pressure inside the bottle has been consumed by the flame of the lit match, it creates an air pressure that is lower in the bottle when compared to the outside of the bottle.

Since the air pressure on the outside of the bottle is higher, it forces the egg down and into the bottle.

## 4. Fountain Bottle

### Materials

• 2-Liter soda bottle
• Water
• Straw
• Clay

### Directions

Here, you’ll learn about adding air pressure to something and the effect this creates.

1. Take your 2-liter bottle and fill it halfway with water.
2. Then take a long straw and place it into the bottle through the mouth.
3. To seal the straw in place, wrap a clump of clay around the mouth to create a seal.
4. Blow hard into the straw and then make sure to stand back.

When you blow air into the straw, you’re increasing the amount of air pressure inside the bottle – this causes the water inside the bottle to push up and through the straw.

## 5. Book-Blowing Experiment

With this book-blowing experiment, you’ll learn just how powerful compressed air can be.

### Materials

• A large plastic bag that you can make airtight.
• Three books.

### Directions

1. Take your three books (it doesn’t matter which ones they are) and stack them on top of each other.
2. Ask the participants of the experiment to move the books by blowing in their direction. Of course, they won’t be able to move them.
3. Then, you’ll want to take your plastic bag and place the three books on top of it. The opening of the bag should hang over the edge of the table.
4. Show the participants that with enough force, then books will be able to lift from the table thanks to the compressed air into the bag.

## 6. Ping-Pong Funnel

### Materials

• A ping pong ball.
• Funnel.

### Directions

1. Place a ping pong ball inside the widest part of the funnel.
2. Using the narrow end of the funnel, blow hard.
3. Here, you should notice that the ball doesn’t pop out – why?

Well, this is because when you blow into the funnel, the air is moving faster and causes the air pressure under the ball to lower.

Therefore, since the air pressure above the ball is higher than the air pressure below it, it is pushed down into the funnel.

Regardless of how hard you blow or in what direction, the ball won’t be able to pop out.

## Final Thoughts

Air is all around us and there is no denying its importance. Another notion is air pressure. Despite the general pressure being 14.7 pounds, this can be altered by a number of factors.

With the help of some fun science experiments, you can teach your children or students everything they need to know about air pressure and how different factors affect it.

Hopefully, this guide has provided you with some inspiration for air pressure experiments.

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